Relations of core parameters. Top panels: peak column density and mean density plotted against the mass. Bottom panels: mean density and mass plotted against the equivalent radius. The red and blue colors always show the data for ISOSS22478 and ISOSS23053, respectively. The full pentagons show the results estimated assuming constant temperatures (T_20K) whereas the crosses present the data assuming the temperatures derived from the H₂CO line data (). The bottom-left panel presents as green line a fit to the data following the approach. Bottom-right panel: fits to the data (green continuous lines) and lines of constant mean column density and constant mean density (dashed and dotted lines, respectively) as labeled in the plot. Respective error-bars in each panel correspond to a factor of 2 uncertainty for masses, column densities, and mean densities, as well as 1 kpc distance uncertainty for the equivalent radii (resulting in the different error-bar end markers for the radii).